这里写目录标题

• 项目介绍
• 功能
• 环境
• 代码

项目介绍

FTP服务器（File Transfer Protocol Server）是在互联网上提供文件存储和访问服务的计算机，它们依照FTP
协议提供服务。 FTP是File Transfer Protocol(文件传输协议)。 程序运行，服务端不断接收客户端指令，服务
端可同时处理多个客户端接入并对指令作出解析，并把执行结果返回给客户端，客户端根据服务端对指令的
解析并把由服务端传递过来的处理信息通过客户端呈现给客户，实现文件的各种操作。

Linux网络编程实现的FTP服务器，服务器由服务端和客户端组成，具有浏览远程服务端的文件和浏览客户端本地文
件，同时支持对远程服务端文件的删除，存储，归档操作处理，以及客户端对远程服务端文件的上传和下载。

功能

ls———查看服务端文件
lls———查看客户端自己的文件
cd———切换服务端目录
lcd———切换客户端自己的目录
put———上传文件
get———下载文件
g———客户端退出

环境

ubuntu充当服务器，树莓派当做客户端使用套接字连接，它们的ip得在同一个网段下，在一个局域网里，连接之前，可以互相ping一下，看看能不能ping通。

代码

ftp_ser.c

#include 
#include 
#include 
#include           /* See NOTES */
#include 
#include 
#include 
#include 
#include 
#include 
#include 
void * server_handler(void * arc);
char *getbehind(char *cmd);
int choose(char * cmd);
void getmessage(char *title,int newfd);
void putmessage(char *title,int newfd);
void choosecmd(char *cmd,int newfd);//使用线程来处理指令 
void * server_handler(void * arc)
{int newfd=*(int *)arc;char* cmd=(char *)malloc(128);while(1){read(newfd,cmd,20);printf("%s\n",cmd);choosecmd(cmd,newfd);memset(cmd,0,128);}
}
char * getbehind(char cmd[128])
{char *p;p=strtok(cmd," ");//以空格键为分隔符，获得分离后的数据。p=strtok(NULL," ");//NULL表示继续往下分隔return p;
}int choose(char * cmd)
{if(!strcmp("lls",cmd))           {   return 1;}else if(strstr(cmd,"lcd")!=NULL) {   return 2;}else if(!strcmp("g",cmd) )        {   return 3;}else if(!strcmp("ls",cmd) )       {   return 4;}else if(strstr(cmd,"cd")!=NULL)  {   return 5;}else if(strstr(cmd,"get")!=NULL) {   return 6;}else if(strstr(cmd,"put")!=NULL) {   return 7;}
}void choosecmd(char cmd[128],int newfd)
{       FILE * fp;int ret=choose(cmd);char *title=(char *)malloc(128);char *readbuf=(char *)malloc(8000);char *p=(char *)malloc(8000);int sfd;switch(ret){case 1:printf("客户端查看客户端的当前目录包含的文件\n");break;case 2:printf("客服端切换进对应目录\n");break;case 3:printf("客户端退出连接\n");break;case 4:fp=popen("ls","r");fread(readbuf,8000-1,1,fp);printf("%s\n",readbuf);write(newfd,readbuf,8000);printf("ls success\n");memset(readbuf,0,8000);break;case 5:title=getbehind(cmd);chdir(title);printf("切换目录成功\n");memset(title,0,8000);break;case 6:title =getbehind(cmd);printf("%s\n",title);if(access(title,F_OK)==-1){write(newfd,"NO file",strlen("NO file"));printf("no file\n");}else{sfd=open(title,O_RDWR,0666);read(sfd,p,8000);write(newfd,p,8000);close(sfd);memset(p,0,8000);printf("服务器已发送文件\n");}break;case 7:title=getbehind(cmd);read(newfd,readbuf,8000);if(strlen(readbuf)!=strlen("NO file")){sfd=open(title,O_RDWR|O_CREAT,0666);write(sfd,readbuf,strlen(readbuf));printf("服务器已接收文件\n");close(sfd);memset(readbuf,0,8000);}else{printf("NO file\n");}break;}
}
int main(int argc,char **argv)
{if(argc != 3){perror("argc");exit(1);}int s_fd;//1.创建套接字s_fd=socket(AF_INET,SOCK_STREAM,0);//2.bind绑定地址struct sockaddr_in maddr;maddr.sin_family=AF_INET;maddr.sin_port=htons(atoi(argv[2]));maddr.sin_addr.s_addr=inet_addr(argv[1]);bind(s_fd,(struct sockaddr *)&maddr,sizeof(maddr));//3.listen允许被连接listen(s_fd,5);struct sockaddr_in caddr;while(1){bzero(&caddr,sizeof(caddr));//清除数据socklen_t p=sizeof(caddr);printf("waiting connected\n");//4.等待被连接int newfd=accept(s_fd,(struct sockaddr *)&caddr,&p);if(newfd < 0){perror("accept");exit(1);}char ipv4_addr[16];//用来存放接受到的客服端的地址if(inet_ntop(AF_INET,(void *)&caddr.sin_addr,ipv4_addr,sizeof(caddr))==0){perror("inet_ntop");exit(1);}printf("get connect:%s,%d\n",ipv4_addr,ntohs(caddr.sin_port));pthread_t pid;pthread_create(&pid,NULL,&server_handler,(void *)&newfd);}return 0;
}

ftp_cli.c

#include 
#include 
#include 
#include           /* See NOTES */
#include 
#include 
#include 
#include 
#include 
#include 
char *getbehind(char *cmd);
int choose(char * cmd);
void getmessage(char *title,int newfd);
void putmessage(char *title,int newfd);
void choosecmd(char *cmd,int newfd);//获取指令中的第二个字符串，如cd ftp，就会获取ftp
char * getbehind(char cmd[128])
{char *p;p=strtok(cmd," ");//以空格键为分隔符，获得分离后的数据。p=strtok(NULL," ");//NULL表示继续往下分隔return p;
}
//获取数据
void getmessage(char cmd[128],int c_fd)
{char *readbuf=(char *)malloc(8000);read(c_fd,readbuf,8000);char *p=getbehind(cmd);printf("%s\n",p);if(strlen(readbuf) != strlen("NO file")){int fd = open(p,O_RDWR|O_CREAT,0666);write(fd,readbuf,strlen(readbuf));printf("recevie successful\n");memset(readbuf,0,sizeof(p));close(fd);}else{printf("NO file\n");}
}
//输出数据
void putmessage(char  cmd[128],int c_fd)
{char writebuf[8000]={'\0'};char *p=(char *)malloc(128);int fd;p=getbehind(cmd);printf("%s\n",p);if(access(p,F_OK)==-1)//判断当前目录是否存在p数组里对应的文件{printf("No file\n");}else{fd=open(p,O_RDWR,0666);read(fd,writebuf,8000);write(c_fd,writebuf,strlen(writebuf));close(fd);memset(writebuf,0,8000);}
}//用来选择指令操作
int choose(char * cmd)
{if(!strcmp("lls",cmd)){return 1;}else if(strstr(cmd,"lcd")!=NULL){return 2;}else if(!strcmp("g",cmd)){return 3;}else if(!strcmp("ls",cmd)){return 4;}else if(strstr(cmd,"cd")!=NULL){return 5;}else if(strstr(cmd,"get")!=NULL){return 6;}else if(strstr(cmd,"put")!=NULL){return 7;}
}
void choosecmd(char *cmd,int c_fd)
{int ret=choose(cmd);char *readbuf=(char *)malloc(128);//char *p=(char *)malloc(8000);char p[8000]={'\0'};switch(ret){case 1:system("ls");//      printf("ok\n");break;case 2: readbuf=getbehind(cmd);chdir(readbuf);memset(readbuf,0,128);break;case 3: printf("exit connect\n");write(c_fd,"away host",8000);close(c_fd);exit(1);break;case 4:read(c_fd,p,sizeof(p));printf("%s\n",p);memset(p,0,8000);break;case 5:printf("host folder open or exit sucessful\n");break;case 6:getmessage(cmd,c_fd);break;case 7:putmessage(cmd,c_fd);break;}
}
int main(int argc,char **argv)
{if(argc != 3){perror("argc");exit(1);}int c_fd;//1.创建套接字c_fd=socket(AF_INET,SOCK_STREAM,0);if(c_fd < 0){perror("socket");exit(1);}struct sockaddr_in saddr;saddr.sin_family=AF_INET;saddr.sin_port=htons(atoi(argv[2]));saddr.sin_addr.s_addr=inet_addr(argv[1]);if(connect(c_fd,(struct sockaddr *)&saddr,sizeof(saddr))<0){perror("connect");exit(1);}printf("connect...... \n");char *writebuf=(char *)malloc(128);while(1){gets(writebuf);//read( _STDIO_H,writebuf,128);printf("cmd:%s\n",writebuf);write(c_fd,writebuf,strlen(writebuf));choosecmd(writebuf,c_fd);printf("*********cmd***********\n");memset(writebuf,0,128);}
}